Not knowing your mechanical prowess, I would say, yes you could probably install it, but if there is any problems, would you know how to find and correct them? Some parts need fitting or could be found unsafe. Another thought...you could always put it back to the way it was, right?

Yes, it will wear in. You'll see where the boss on the safety bears against the sear if you take it out. What's Kimber running now, a Swensen-style? I prefer the Kings method of offside lever retention.